Field of the Invention
The present invention relates to a liquid crystal display, and particularly relates to a liquid crystal display of the lateral electric field type.
Description of the Background Art
A liquid crystal display typically includes a backlight as a light source. The backlight is disposed opposite to a display screen of the liquid crystal display provided with a pair of substrates. The liquid crystal display causes a light beam emitted from the backlight to transmit therethrough so as to display a desired still or moving image. The two substrates enclose liquid crystal therebetween. A first one of the substrates is an array substrate having a plurality of pixels arranged in a matrix state. A second one of the substrates is a counter substrate provided with a color filter, a black matrix (light shielding film), and the like. The array substrate and the counter substrate are stuck to each other by a sealing material. The liquid crystal display has a display area and a non-display area (also called a frame area) surrounding the display area. The non-display area is provided with the black matrix serving as a light shielding layer to suppress leakage of a light beam emitted from the backlight.
In recent years, the in-plane switching (IPS) mode and the fringe field switching (FFS) mode of the lateral electric field type, which is excellent in view angle property have been widely adopted in place of the twisted nematic (TN) mode according to the conventional vertical electric field system. A liquid crystal display in the IPS mode or the FFS mode includes an array substrate (first substrate) and a counter substrate (second substrate) which are disposed opposite to each other with a liquid crystal layer being interposed therebetween. The array substrate is provided, on the surface facing the liquid crystal layer, with a pixel electrode and a common electrode so as to be insulated from each other. The pixel electrode and the common electrode are configured to drive the liquid crystal. The pixel electrode and the common electrode apply, to liquid crystal molecules, an electric field in a substantially transverse direction (along the surface). The paired electrodes in the IPS mode are not overlapped with each other in a planar view. In contrast, the paired electrodes in the FFS mode are overlapped with each other in a planar view.
In the liquid crystal display in the IPS mode or the FFS mode, the first electrode is provided with the pixel electrode and a counter electrode, and the second electrode is provided, on the surface facing the liquid crystal, with insulating films such as a black matrix made of organic resin, an overcoat, a color filter, and the like. Unlike the liquid crystal display in the TN mode, the counter substrate is provided with no counter electrode (common electrode). When static electricity is induced to the counter substrate from the outside, an electric field generated by the static electricity is applied to the liquid crystal layer and causes abnormal displaying.
The first substrate is provided, in the frame area, with an inspection circuit (e.g. a lighting inspection circuit) or a protection circuit (e.g. a short ring circuit). Gate lead-out wires provided to switch the circuit generates an electric field that causes electric potential fluctuation of the second substrate and uneven displaying.
In view of the above problem, Japanese Patent Application Laid-Open No. 2005-275054 discloses provision of a shield electrode (conductive film) configured to shield an electric field, on gate lead-out wires of an array substrate with an insulating film being interposed therebetween, to prevent uneven displaying. Japanese Patent Application Laid-Open No. 2011-170134 discloses division of a black matrix in a non-display area to prevent entry of static electricity of the black matrix.
In the configuration according to Japanese Patent Application Laid-Open No. 2005-275054, a shield electrode cannot be provided to a connection conversion part, which is disposed at a connection between a wire layer for an inspection circuit, a protection circuit, or the like and a gate wire. The connection conversion part in a panel with high dot density has high density and a larger area. The defect mentioned above is caused around the display area in the vicinity of the connection conversion part.